The British Parliament passed a law granting independence in July 1947. The law gave people only one month to decide which country they wanted to live in and to move there. As millions of people began to move, more violence broke out.
Calderas form when an enormous magma chamber under, what was probably a pretty ginormous volcano, empties and collapses, causing the land above it to collapse as well. An explosive caldera-forming eruption has never been witnessed first hand, but we know that they should pretty fearsome spectacles. Much smaller calderas atop effusive volcanoes (hawaiian style) have been observed. So, formation: maars form when a vent intersects groundwater and blasts out the overlying material.
The 1980 eruptive episode of Mount St. Helens included more than one type of eruptive behavior and more than one kind of volcanic hazard. It is not uncommon for volcanoes to exhibit a range of eruptive types during an eruption. Copyright (C) 1997, by Richard V. Fisher.